Automatic control unit for vacuum cleaners



3 Sheets-Sheet l w. wax V A. P. CAWL AUTOMATIC CONTROL UNIT FOR VACUUMCLEANERS o 0 0 o m w m o o 0 0 .0 wol wp w% 0 April 10, 1956 Filed April7, 1954 April 10, 1956 A. P. CAWL AUTOMATIC CONTROL UNIT FOR VACUUMCLEANERS Filed April 7, 1954 3 Sheets-Sheet 2 INVENTOR 4((6771? Cfll/ZORNEY April 10, 1956 A. P. CAWL 2,741,328

AUTOMATIC CONTROL UNIT FOR VACUUM CLEANERS Filed April 7, 1954 5Sheets-Sheet 5 United States Patent AUTOMATIC CONTRGL UNIT FOR VACUUMCLEANERS Allen P. Cawl, Stamford, Conn, assignor to ElectroluxCorporation, Old Greenwich, Conn., a corporation of Delaware ApplicationApril 7, 1954, Serial No. 421,481

Claims. (Cl. 183-37) This invention relates to vacuum cleaners and moreparticularly to such cleaners as have automatic means for controllingcertain operations of the cleaner in accordance with predeterminedvariations in air pressure resulting from dust and dirt collectedtherein during use.

In a preferred embodiment of this invention a single diaphragm functionsfirst as a differential pressure responsive member which upon continuedmovement opens valve means enabling pressure, either atmospheric orhigher, to act positively on one surface of the differential pressureresponsive diaphragm. This results in such added power that the samediaphragm functions both as a control diaphragm and as a powerdiaphragm. In its latter function it may be used to deenergize the motorfan unit, open the front cover, eject the dust container or merely causethe operation of a visible or audible signal.

It is another object of this invention to make the valve operated by thedifierential pressure phase of the diaphragms operation adjustable sothat the pressure differential at which it discontinues functioning as adifierential pressure responsive member and begins to function as apower diaphragm may be varied over a predetermined range of values. Thisis efiected by providing a screw threaded member having a communicationto the exterior which may be raised or lowered at will to cooperate withan open central core whereby communication can be established with afurther pressure source so as to predetermine the point of more positiveand rapid diaphragm operation.

Further objects and additional advantages of this in vention will becomeobvious to those skilled in the related art upon reading the followingdescription together with the appended drawings wherein:

Figure 1 is a side view, chiefly in section, showing a preferredembodiment of this invention; v

Figure 2 is a top plan view, somewhat enlarged, of the control unit andfront cover in open position of the vacuum cleaner shown in Fig. 1;

Figure 3 is a cross-section, somewhat enlarged, taken on the line 33 ofFig. 2;

Figure 4 is a cross-section on an enlarged scale taken on the line 44 ofFig. 2, showing the valve closed; and

receiving compartment 22 shown perforated with apertures 24 for freepassage of suction air current therethrough. Inner body 22 is secured atone end to front body ring 26 which in turn is secured within the openend of outer body 10.

The lower part of front body ring 26 forms the de- 2,741,328 FatentedApr. 10, 1956 pending front wall 28 and part of the bottom of controlchamber 34). Removable stamping 31 completes the enclosure of chamber30. Front cover 34 is hinged by pin 36 to a pair of projections 32extending from the wall 28 and is biased to open position by spring 38.A hose coupling assembly 42 is pivotally mounted by pins 44 in theopening 40, Fig. 2, formed in the cover. Link 48 pivotally connected tothe hose coupling assembly at one end and to a projection 32 at theother end forms a parallel motion linkage which causes the hose couplingassembly 42 to move parallel to itself upon opening and closing thecover 34.

Hose coupling assembly 42 effects an airtight seal with front body ring26 by means of the stiff cardboard disc 58 of dust bag or dustseparating member 56 with the aid of gasket 54 bearing against the disc58 while theedges of disc 58 seal against gasket 60 carried by frontbody ring 26. Tubular member 52 of hose coupling assembly 42 extendsthrough a centrally disposed opening in disc 58 when the cover is in theclosed position shown in Fig. l in order to introduce the air andentrained dust directly into the interior of dust bag 56.

A differential pressure diaphragm housing 64 secured below body 10 by aplurality of bolts 62 forms a combined control unit and power diaphragmactuating member. Secured within housing 64 is a pressure differentialdiaphragm 68, Figs. 4, 5, which divides the housing into an upper highvacuum chamber '70 and into a lower low vacuum chamber 72. Chamber 7% isconnected to the interior of body 10 through an opening 74 in the bodyhousing 10. The edges of diaphragm 6S bear against the bottom of body 16and housing 64 seals against diaphragm 68 to prevent leakage.

A flexible conduit 88 connects the lower chamber 72 and a passage in thehose connector 42 to subject the lower surface of the diaphragm 68 tothe pressure existing within or ahead of the bag 56, while the uppersurface of diaphragm 68 is subjected to the pressure existing within thebody iii between the bag and the fan unit, except when the pressure inchamber 72 is modified by atmospheric pressure or other pressureintroduced by the opening of valve means in member 114 described below.

Spring 92 is disposed between the upper surface of diaphragm 68 and thelower wall of body 10. Diaphragm 68 carries a stem and secured to thelower end of this stem 110 is a valve member 112 which controls the flowof atmospheric pressure or other pressure from port 113 through a bore111 connecting the interior of hollow member 114 with low suctionchamber 72. Hollow member 114 is adjustably mounted by threads 115 so asto raise and lower the position of port 113 with respect to sealingvalve member 112.

Within the body 14 adjacent to opening 74 is a bracket 116 in which ispivotally mounted a pin 134 carrying a rocker arm 118 one end of whichis disposed above the stem 110 of the diaphragm 68. The other end of arm118 bears against a pin 120 slidably mounted in the bracket 116. Thelower end of pin 124 bears against the inner end of front cover latch122 which is pivotally mounted on wall 28 at 124. The outer end of latch122, Fig. 4, is formed with a shoulder 123 which is adapted to engage akeeper 134 mounted on the front cover 34 so as to retain the cover inclosed position. A spring 132 urges the latch arm 122 towards theposition shown in full lines in Fig. 4. I Oneend of pin 134 extends toone side of bracket 116, where it is provided with a cam 136. This cambears against a leaf spring 133, one end of which is secured to thebottom wall of housing 10, while the free end of the spring carries astop 140.

The bottom wall of inner body 22 is formed with 3 an elongated slot 142,Fig. 1, in which is disposeda cylindrical rail 144, the front end ofwhich is secured to the ring 26, while the rear end is secured to therear wall of the inner body. Slidably mounted on the rail 144 is anejector member 146. A normally flat leaf spring 148 is disposed betweenthe rear wall of the inner body and the ejector member and tends to movethe latter towards the left, as viewed in Fig. l. Slidably mounted belowthe rail 144 is a latch bar 150 near the rear end of which is secured aleaf spring 152. Ejector 146 is formed with a lip 154 which, in theposition of the parts shown in Fig. l, is engaged by the spring 152. Thefront end of the latch bar 150 abuts against the stop 140 so as toretain the ejector 146 in its rearward latched position with the spring148 compressed. A bracket 1S6 carried by the rear wall of the inner bodyis formed with a lower inclined surface 158 so arranged with respect tothe spring 152 that movement of the latch bar 150 to theleft causes theinclined surface to cam the free end of the spring 152 downwardly andout of engagement with the lip 154 of the ejector, thus releasing thelatter for movement by its spring 148.

An electric switch 160 is provided for controlling the supply of currentto the motor 16. 'This switch may be manually actuated by means of apivoted member 162. In the position shown in Fig. l, the switch is offand pivoting of the member 162 in a clockwise direction serves to closethe switch. Slidably mounted adjacent the switch 172 extending outwardlyfrom the switch actuating member 162 when the latter is in the onposition. Thus, if the switch is on and the front cover is opened, thebar 164 moves to the left under the influence of its spring 166 and arm170 contacts pin 172 so as to throw the switch automatically to the offposition.

The above described control device operates as follows:

With parts in the position shown in Fig. 1, that is with a clean dustbag in 'place within the body and the front cover closed, operation ofthe motor-fan unit serves to draw air in through the inlet 52. This airpasses with but little resistance through the porous material of the bagand through the many openings 24 of the inner body to the inlet 20 ofthe fan 14. The pressure existing within the inlet is communicatedthrough the opening 90 and conduit 88 to the chamber 72 below thepressure diiferential diaphragm 68. The pressure existing "within theinner body between the bag and the inlet of the fan is communicated tothe chamber 70 above the diaphragm 68 through the opening 74. Thusdiaphragm 68 is subjected to the differential pressure resulting fromthese two pressures, which corresponds to the pressure .drop through thedust bag. When the bag is clean there is but little pressure dropthrough it and consequently this different'ial is very small and is notsuflicient to displace the diaphragm upwardly against the force of thespring 92.

However, as more and more dirt is introduced into the bag with theincoming air, it is retained within the bag and gradually clogs thepores thereof so as to increase the pressure drop. This of courseincreases the differential pressure acting on the diaphragm 68 andstarts to raise the latter by compressing the spring 92. The more'th'isspring is compressed the greater is the resistance which between the lowvacuum chamber 72 and the at mosphere or some other source of positivepressure. This causes the difierential pressure diaphragm 68 to movequickly and more powerfully to its upper limit, 'thus functioning as apower diaphragm. With the device of this invention high vacuum is alwaysapplied directly to the upper surface of diaphragm 68.

Upwardmovement of the power diaphragm causes its stem 110 to pivot thearm 118 in a counterclockwise direction, as viewed in Fig. 4. Thisdepresses the pin 120 which in turn pivots the latch 122 in clockwisedirection so as to disengage it from the keeper of the front cover. Thespring 38 thereupon opens the cover and when this occurs the projection168 on the bar 164 is released and the spring 166 moves the bar to theleft, as seen in Fig. 1, thus moving the switch member 162 to its offposition, which stops the operation of the motor-fan unit.

Pivoting of the arm 118 causes pin 134 to turn in a counterclockwisedirection, as viewed in Fig. 3, thus causing cam 136 to depress thespring 138, which with draws the stop 140 from contact with the left endof the ejector latch bar 150. As the right-hand .end of this bar iscoupled to the ejector through engagement of the leaf spring 152 withthe lip 154, the release of latch bar causes ejector spring 148 to moveboth the ejector 146 and the bar 150 to the left. The inclined surface158 on the bracket 156 thereupon cams the spring 152 down wardly and outof engagement with the lip 154, whereupon the ejector is freed to moveall the way to the left, pushing the bag ahead of it and out of thecleaner.

By adjusting the relative positions of valve 112 with respect to port113 a greater or lesser pressure drop through the bag will be requiredin order to establish the pressure differential necessary to causediaphragm 68 to open valve 112. The lower hollow member 114 isadjust-able with respect to housing 64 by virtue of its threadedconnection 115. Thus the lower port 113 is dis placed by screwing thehollow member outwardly, the lower will be the pressure differential ordrop through the bag required to open valve 112 and admit positivepressure to chamber 72.

It is to be understood that the embodiment herein specifically describedis merely illustrative and that the scope of the invention is to belimited solely by the suction chamber and a high suction chamber,conduit means for connecting said low suction chamber to a point in saidcasing ahead of said dust separating means, conduit means for connectingsaid high suction chamber with a point in said casing between said dustseparating means and said suction producing means, valve means openableby displacement of said diaphragm in a direction towards said highsuction chamber to establish communication between said low suctionchamber and a region of higher pressure for decreasing the suction insaidlow suction chamber to further displace said diaphragm in saiddirection, and means responsive to the further displacement forcontrolling said vacuum cleaner.

2. in combination with a vacuum cleaner having a casing enclosing dustseparating means and suction proit' offers to further compression andthe spring is so selected with respect to the area of diaphragm 68 thatthe diaphragm will open the valve 112 when the pressure drop through thebag has attained a value such that continued operation of the cleanerwould be inefiicient.

When diaphragm 63 moves high enough to lift the lower seal of valve 112above port 113, as in ,Fig. 5, cornrnunication is established throughthe bore 111 of stem ducing means for causing how of air therethrough, ahousing, a diaphragm dividing said housing into a low suctic'm chamberand a high suction chamben'conduit means for connecting .said lowsuction chamber to .apo'int in said casing ahead of said dust separatingmeans, conduit means for conn cting said high suction chamber wlithapoint in said casing between said dust separating means and saidsuctionproducing means, valve means opcnable by a predetermineddisplacementof sa'id diaphragm in a direction towards said high suctionchamber to establish communication between said low suctionw chamber anda region of higher pressure for decreasing the suction in said lowsuction chamber to further displace said diaphragm in said direction,means responsive to the further displacement for controlling saidvacuum' cleaner, and manually adjustable means for varying thedisplacement of said diaphragm required to open said valve means.

3. In combination with a vacuum cleaner having a casing enclosing dustseparating means and suction producing means for causing flow of airtherethrough, a housing, a diaphragm dividing said housing into a lowsuction chamber and a high suction chamber, conduit means for connectingsaid low suction chamber to a point in said casing ahead of said dustseparating means, conduit means for connecting said high suction chamberwith a point in said casing between said dust separating means and saidsuction producing means, a hollow member having a port connecting theinterior of said member with a region of higher pressure, a stemextending into said hollow member and being movable by displacement ofsaid diaphragm in a direction towards high suction chamber to establishcommunication between said port and said low suction chamber fordecreasing the suction in the latter to further displace said diaphragmin said direction, and means responsive to the further displacement forcontrolling said vacuum cleaner.

4. In combination with a vacuum cleaner having a casing enclosing dustseparating means and suction producing means for causing fiow of airtherethrough, a housing, a diaphragm dividing said housing into a lowsuction chamber and a high suction chamber, conduit means for connectingsaid low suction chamber to a point in said casing ahead of said dustseparating means, conduit means for connecting said high suction chamberwith a point in said casing between said dust separating means and saidsuction producing means, a hollow member having a port connecting theinterior of said member with a region of higher pressure, a stemextending into said hollow member and being movable by displacement ofsaid diaphragm in a direction towards said high suction chamber toestablish communication between said port and said low suction chamberfor decreasing the suction in the latter to further displace saiddiaphragm in said direction, means responsive to the furtherdisplacement for controlling said vacuum cleaner, and means foradjusting the position of said hollow member with respect to said stemto vary the displacement of said diaphragm required to establish saidcommunication.

5. In combination with a vacuum cleaner having a casing enclosing dustseparating means and suction producing means for causing flow of airtherethrough, a housing, a diaphragm dividing said housing into a lowsuction chamber and a high suction chamber, conduit means for connectingsaid low suction chamber to a point in said casing ahead of said dustseparating means, conduit means for connecting said high suction chamberwith a point in said casing between said dust separating means and saidsuction producing means, a hollow member having a port connecting theinterior of said member with a region of higher pressure, a stem securedto said diaphragm and extending into said hollow member and normallyclosing said port, said stem having a bore connecting the interior ofsaid hollow member with said low suction chamber, said stem beingmovable in said hollow member by displacement of said diaphragm in adirection towards said high suction chamber to open said port andestablish comunication from the port through said bore to said lowsuction chamber for decreasing the suction in the latter to furtherdisplace said diaphragm in said direction, and means responsive to thefurther displacement for controlling said vacuum cleaner.

6. In combination with a vacuum cleaner having a casing enclosing dustseparating means and suction producing means for causing flow of airtherethrough, a housing enclosing said diaphragm dividing said housinginto a low suction chamber and a high suction chamber, conduit means forconnecting said low suction chamber to a point in said casing ahead ofsaid dust separating means, conduit means for connecting said highsuction chamber with a point in said casing between said dust separatingmeans and said suction producing means, a hollow member having a portconnecting the interior of said member with a region of higher pressure,a stem secured to said diaphragm and extending into said hollow memberand normally closing said port, said stem having a bore connecting theinterior of said hollow member with said low suction chamber, and saidstem being movable in said hollow member by displacement of saiddiaphragm in a direction towards said high suction chamber to open saidport and establish communication from the port through said bore to saidlow suction chamber for decreasing the suction in the latter to furtherdisplace said diaphragm in said direction, means responsive to thefurther displacement for controlling said vacuum cleaner, and means foradjusting the position of said hollow member with respect to said stemto vary the displacement of said diaphragm required to cause said stemto open said port.

7. In a vacuum cleaner, a casing, dust separating means and suctionproducing means disposed in said casing, a diaphragm housing secured tosaid casing, a diaphragm dividing said casing into a high suctionchamber and a low suction chamber, said casing being formed with anopening from said high suction chamber into a space within said casingbetween said dust separating means and said suction producing means,means for establishing communication between said low suction chamberand the interior of said casing ahead of said dust separating means, ahollow member secured to said diaphragm housing and communicating withsaid low suction chamber and having a port opening to atmosphere outsidesaid casing, a stem secured to said diaphragm and extending into saidhollow member and normally closing said port, said stem having a boreconnecting the interior of said hollow member with said low suctionchamber, said stem being movable by displacement of said diaphragmtowards said high suction chamber to open said port to admit air atatmospheric pressure to said low suction chamber for decreasing thesuction therein to further displace said diaphragm in said direction,and means responsive to the further displacement for controlling saidvacuum cleaner.

8. In a vacuum cleaner, a casing, dust separating means and suctionproducing means disposed in said casing, a diaphragm housing secured tosaid casing, a diaphragm dividing said casing into a high suctionchamber and a low suction chamber, said casing being formed with anopening from said high suction chamber into a space within said casingbetween said dust separating means and said suction producing means,means for establishing communication between said low suction chamberand the interior of said casing ahead of said dust separating means, ahollow member having an open end in threaded engagement with saiddiaphragm housing and communieating with said low suction chamber, saidhollow member having a port opening to atmosphere outside said casing, astem secured to said diaphragm and extending into said hollow member andnormally closing said port, said stem having a bore connecting theinterior of said hollow member with said low suction chamber, said stembeing movable by displacement of said diaphragm towards said highsuction chamber to open said port to admit air at atmospheric pressureto said low suction chamber for decreasing the suction therein tofurther displace said diaphragm in said direction, and means responsiveto the further displacement for controlling said vacuum cleaner, saidhollow member being accessible for manual rotation to adjust itsposition axially with respect to said stem to shun-see" vary thedisplacement, of said diaphragm necessary to cause said stem to opensaid port. a

9, In a vacuum cleaner, a casing, dust separatingmeans and suctionproducing means disposed in a space in said casing, ejector mechanismdisposed in said space and releasable for ejecting said dust separatingmeans from said casing, a diaphragm housing secured to said casing, a;diaphragm dividing said easing into a high suction chamber and a lowsuction chamber, said casing being formed with an opening from said highsuction chamber into a space within said casing between said dustseparating means and said suction producing means, means forestablishing communication between said low suction chamber and theinterior of said casing ahead of said dust separating means, a hollowmember secured to said (Ha pbragm'housing and communicating with saidlow suction chamber and having a port to a region of higher pressure, astemsecured to said diaphragm and extending into said hollow member andnormally closing said port, said stem having a bore connecting theinterior of said hollow member with said low suction chamber, and saidstem being movable by displacement ot' 'said diaphragm towards said highsuction chamber to open said port to admit air from said region ofhigher pressure to said low suction chamber for decreasing the suctiontherein to further displace saiddiaphragm in said direction, a rodextending sing diaphragm, ,aivr s chamber into a spacelwithin saidcasingfbetween said dust separating means and said suction producingmeans, a means for establishing communication between said lowsuction-chamber and the interior of said casing ahead of said dustseparating'means, a hollow member having an open end in threadedengagement with said diaphragm housing and communicating with said lowsuction chamher, said hollow, member having a port to a region of higherpressure in the side thereof, a stem secured to said diaphragm andextending into said hollow member and normally closingsaid port, saidstem having a bore connecting the interior of said hollow member withsaid low suction chamber, said stem being movable by displace mechanism,said hollow member being accessible =formanual rotation to adjust itsposition axially with respect to said stem to vary the displacement ofsaid diaphragm necessary to cause said stem to open said port.

References Cited in the file of this patent STATES PATENTS 2,569,222"Beede et al. Sept. '25, 1951 FOREIGN PATENTS Great Britain Dec. ll,1931 said casing into saga, suction chamber and a low suction chamber,said casing being formed with .an opening from said high suction

